opam from env

gistfile1.txt

(defun opam-from-env ()
       "Set environment and Emacs `exec-path' and `load-path' variables according to the opam configuration of the current working directory."
       (interactive nil)
       (let* ((opam-config (car (read-from-string (shell-command-to-string "opam config env --sexp"))))
              (_ignore (dolist (var opam-config) (setenv (car var) (cadr var))))
              (opam-switch-prefix (file-name-as-directory (getenv "OPAM_SWITCH_PREFIX")))
              (opam-path-p (lambda (p) (string-match-p "/[._]opam/" p)))
              (opam-path
               (car (seq-filter opam-path-p (split-string (cadr (assoc "PATH" opam-config)) ":"))))
              (f (lambda (d) (if (funcall opam-path-p d) opam-path d)))
              (g (lambda (d) (replace-regexp-in-string
                              ".*/[._]opam/.*/share/emacs/site-lisp"
                              (concat opam-switch-prefix "/share/emacs/site-lisp") d))))
         (setq exec-path (mapcar f exec-path))
         (setq load-path (mapcar g load-path))))